Just a few years ago, this 1840 hacienda was a shadow of its former self. Junk filled the garden, walls crumbled. But in the right hands, the adobe and its rich history are revived.

Outside, Pomona shimmers, roastingly hot. But walk in under the spread of the Alvarado adobe's ancient trees and you'll swear the temperature drops 10 degrees. Now, as your sun-bleared eyes adjust, you notice a small group of people sitting in rocking chairs on the corner of the long, green-posted veranda.

"Look as if you could do with a cool drink," says Bruce Coons.

He is only the fourth owner the hacienda has had since it was built 163 years ago by the hugely prominent and wealthy Alvarado family, which owned ranches from San Diego to L.A. It is known to be either the second- or third-oldest house in Los Angeles County that is still a private residence.

This might be the luckiest hacienda in L.A. County: Coons runs SOHO, the San Diego-based Save Our Heritage Organization, the "oldest continually operating preservation organization in California." This adobe, he says, is his dream home, the place he plans to retire to, even though "it could be the greatest fixer-upper of all time."

By 2000, when the Coonses moved in, the adobe was starting to crumble. "And you should have seen this garden. It was knee-deep in junk. Refrigerators, stoves, motor parts, carpets, a mess," he says.

The garden was the first project for Coons' wife, Alana. To bring it back to its 1840 self, she planted California native roses (dubbed "the Rose of Castile" by the Californio families -- early Hispanic settlers of the state -- who couldn't get the real thing from Spain), lavender-like Mexican sage, strong-smelling lemon verbena ("they used it for cooking and medicinal teas"), pomegranates, mission olive trees and a small jungle of edible cactus. "Cactus was traditional for protective hedges around rancho houses," says Bruce Coons. "Rancheros worried about attacks from Yuma and Mojave Indians."

"You should see this in the spring," Alana Coons says. "It's rampant color. Especially the orange California poppies."

But the prize has to be a little gnarled orange tree, with one or two oranges still clinging to its branches. "This is the San Gabriel Mission orange tree," says Bruce Coons. "It has been growing for about 150, maybe 160 years. It's an offspring of the first oranges brought to California."

A stone-lined waterway the Coonses discovered when they finally hauled out all the trash brought water from a marsh nearby. "We're going to get it running again too," says Coons.

The temperature seems to drop 20 degrees more when you walk through the adobe's 3-foot walls and straight into the sala, the grand room of the house. The only way Ygnacio Alvarado got permission to build his house in 1839 was by agreeing to include a room large enough to hold religious services. This was it, and it was the making of Alvarado: The grand room became the social and religious heart of 1840s Pomona valley life.

Indeed, it's so authentic you almost expect to see stuffed dummies in rancho clothing sitting around in a re-created scene. But this is no museum. Smoke stains and dribbled wax tell you the oil lamps and Spanish-looking tin candleholders on the walls are regularly used. The Coonses also brought appropriate furnishings with them, such as a large Mexican painting from the 1750s showing the Christ child in his mother's arms, imbuing a plateful of hearts with love before giving them out to people. And the red, white, blue and green satillo, or serape, from the 1870s, a sophisticated version of a poncho worn by the gentry. And the new-looking 1890s Navajo rugs, whose makers, Coon says, drew their inspiration from the satillos, tossed on the Douglas fir floor timbers.

A favorite place to sleep is the "priest's room," a low-ceilinged sleeping quarter off the dining room that was given over to the priest on his visits. "This whole adobe wall had crumbled," says Coons. "Alana and I made the bricks and rebuilt it."

Which is not as easy as it sounds. "It's pretty backbreaking," he says. "The bricks are about 10 by 20 inches by 4 inches thick. They weigh maybe 20 pounds each. The size goes back to an old Spanish measure." Here they reused the adobe that had crumbled to make the bricks they needed. But if they hadn't been able to do so, Coons says it would have just been a question of digging in the yard. "Most of Southern California [soil] is good for making adobe bricks. A lot of people think that adobe is clay. It's not. It's a combination of clay and sand. You mix it up with water till it gets a Play-Doh kind of consistency. Add straw to help get air into the center of the block so it will dry evenly and not crack, empty into a mold and presto."

The Coonses were lucky. They had to make only a dozen adobe bricks to repair the caved wall of the priest's room. "To build an average house," says Coons, "you'd need about 2,000 bricks." Basically, he says, the technique hasn't changed since the ancient Egyptians, and later the Mission Indians. "We used exactly the same methods the Indians working here 160 years ago would have used."